An in-situ neutron diffraction study of a multi-phase transformation and twinning-induced plasticity steel during cyclic loading

• Published in: Applied physics letters 2015-04, Vol.106 (17)
• Main Authors: Saleh, Ahmed A., Brown, Donald W., Pereloma, Elena V., Clausen, Bjørn, Davies, Christopher H. J., Tomé, Carlos N., Gazder, Azdiar A.
• Format: Article
• Language: English
• Subjects: Alloys; Applied physics; Bauschinger effect; Compressive properties; Crystal lattices; Crystal structure; Crystallographic defects; Cyclic loads; Deformation; ENGINEERING; Interphases; Martensite; Martensitic stainless steels; Martensitic transformations; Neutron diffraction; Neutron scattering; Neutrons; Phase transitions; Plasticity; Strain gauge; TWIP steels; Weight
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4919455

In-situ neutron diffraction during cyclic tension-compression loading (∼+3.5% to −2.8%) of a 17Mn-3Al-2Si-1Ni-0.06C steel that exhibits concurrent transformation and twinning -induced plasticity effects indicated a significant contribution of intragranular back stresses to the observed Bauschinger effect. Rietveld analysis revealed a higher rate of martensitic transformation during tension compared to compression. Throughout cycling, α′-martensite exhibited the highest phase strains such that it bears an increasing portion of the macroscopic load as its weight fraction evolves. On the other hand, the ε-martensite strain remained compressive as it accommodated most of the internal strains caused by the shape misfit associated with the γ→ε and/or ε→α′ transformations.